I believe there is an actual TZ thread in the nitro engine forum. But from what I can tell a lot of people are finding good power in the 180's range. I wouldnt push it much beyond that.
Granted Ive taken my novarossi motor to 270 and it still was fine , its just how this motor goes. Generally 240 is the max you would want to do with any motor. But Ive heard of many people saying this isnt true and they go beyond that , basically looking for power not temps.
I for safe sakes and have heard many people say above 240 is no good. I go for power and then try to keep it cool. But in the case of the TZ , many many times people are keeping them under 200. I would say try to do the same.